Belt sander



April 6, 1954 T. B. THOMAS ET AL BELT SANDER 2 Sheets-Sheet 1 FiledApril 24, 1953 INVENTORfi 2g ATTORNEY in iaZ.,Brow-ra Theodora-BlhomasApril 6, 1954 T. B. THOMAS ET AL BELT SANDER 2 Sheets-Sheet 2 FiledApril 24, 1953 INVENTORS f'heoczorefl Thoma/6 Vz'ryinz'al;

Bro'urn 7 Y a TTURNEY Patented Apr. 6, 1954 UNITED STATES PATENT OFFICEBELT SANDER Theodore B. Thomas and Virginia L. Brown, New London, Wis.

This invention relates to a novel form of belt sander and moreparticularly to a belt sander which is constructed to be utilized as adrill press attachment utilizing the power furnished by the drill pressfor driving the sanding belt including a pulley speed changer, which isconventional with drill presses, for varying the speed at which the beltwill be driven to thereby increase the versatility of the sandingattachment.

Another object of the invention is to provide a sander attachmentwherein tightening of the sander belt may be readily accomplished bymerely shifting a supporting bedplate of the attachment relatively to adrill press table to which the bedplate is clamped.

Other objects and advantages of the invention i.

will hereinafter become more fully apparent from the followingdescription of the drawings, illustrating a presently preferredembodiment thereof, and wherein:

Figure 1 is a side elevational view, partly in section, showing the beltsander attachment in an operative position connected to a conventionalchange speed drill press;

Figure 2 is a top plan view of the sander attachment taken substantiallyalong a plane as indicated by the line 2-2 of Figure 1;

Figures 3 and 4 are enlarged cross sectional views taken substantiallyalong planes as indicated by the lines 3-3 and 4-4, respectively, ofFigure 1;

Figure 5 is a central sectional view, partly in elevation, taken throughthe larger drive spindle of the sander attachment;

- Figure 6 is a fragmentary vertical sectional view of a portion of thebacking plate and the mounting thereof; and

Figure 7 is an'enlarged fragmentary cross sectional view takensubstantially along a plane as indicated by the line 1-1 of Figure 1.

Referring more specifically to the drawings, the

belt sander attachment in its entirety and comprising the invention isdesignated generally l0 and includes an elongated base plate II having anarrow extension I 2 constituting one end thereof and which forms anextension of one side edge I3 of said base plate.

Said narrow end I2 is provided with a pair of transversely spacedupwardly extending apertured standards I4 to receive there'between aportion of an elongated supporting member I5 which is pivotallysupported on said standards I4 by a pivot pin I6 which extendstherethrough and through a portion of the support I5, for rockingmovement of said support in a vertical plane. A substantiallysemicircular end table I! has a slotted bar I8 fixed to and dependingfrom an underside thereof. A bolt of a bolt and wing nut fastening Iiextends through the slot of the bar I8 and through the outer end of therocking support I5 to detachably and adjustably mount the table I'Ithereon. I

The rocking support I5 is provided with an antifriction bearing 2I, asbest illustrated in Figure 7, which is mounted therein between the pivotI6 and its outer end 20 and in which is journalled the lower end of asmall diameter belt spindle 22 which rises substantially perpendicularlyfrom said support 15. A manually adjustable screw 23 is threadeddownwardly through an inner end 24 of the support I 5, inwardly of thepivot I6, and has a lower end which rests normally upon a part of thebedplate portion I2 to limit rocking movement of the support I5 in aclockwise direction as seen in Figure 1. v

The inner straight edge of the end table I! is provided intermediate ofits ends with a notch 25 which is disposed around the spindle 22.

The bedplate I I has a supporting post 26 fixed to'and rising therefromadjacent its side edge l3 and remote to the narrow bedplate end [2. Thepost 26 has fiat sides disposed transversely of the bedplate II and hasa bolt and wing nut fastening 2'! extending therethrough. An elongatedside table 28 has a slotted bar 29 fixed to and depending therefrom anddisposed substantially intermediate of the ends thereof. The bar 29extends downwardly on one side of the post 26 and the bolt of thefastening 21 extends therethrough for adjustably securing the bar 29 tosaid post for supporting the side table 28 thereabove.

A back or backing plate 30 has a pair of legs 3| secured to an inner orback side thereof by fastenings 32. The legs 3| extend downwardly from abottom edge of the backing plate and terminate in right angularly turnedlongitudinally slotted foot portions 33 which extend away from the planeof the backing plate 38 and which rest on the base plate H. Screwfastenings 3d extend loosely through the slots or foot members 33 andthreadedly engage in the base plate H for securing the backing plate asabove said base plate and in a vertical plane, and substantiallylongitudinally of the base plate. 'An outer face 35 of the backing plateso is spaced from the adjacent inner edge 3% or" the side table 28. Saidouter face 35 is shown provided with one groove 31 which extends fromend-to-end thereof; however, the face 35 may be provided with one ormore grooves of different cross sectional sizes and shapes, for apurpose which will hereinafter be apparent.

All of the parts previously described are directly or indirectlysupported by the base plate l l. The wide end of said base plate, whichis located remote to the narrow end portion i2 thereoi,'is adapted torest on a portion of a table 38 of a conventional change speed drillpress, a portion of which is illustrated at 39. Said base plate portionis secured to the drill press table 38 by a conventional clamp 49,adjacent the edge of the base plate which is located remote to saidaforementioned edge It.

' A relatively large drive spindle or pulley M, of a diametersubstantially greater than that of the spindle 22, has an intermediateportion of a shaft or stem 12 extending centrally therethrough andsecured therein. As best seen in Figure 5, the ends of the shaft or stems2 extend from the ends of the spindle or pulley a l. One shaft end 43is larger than the other shaft end 44. Said shaft ends of differentdiameters are adapted to fit drill chucks of different sizes, foradapting the pulley ll to drill presses having chucks of diiierentsizes. As illustrated in the drawings, the larger shaft end 43 is shownsecured in a drill chuck 45 of the drill press 38, in a conventionalmanner, for suspending the pulley .or'spindle H therebeneath. An endlesssanding heltllfi having an abrasive outer surface is trained around thepulleys or spindles ll and 22 with one flight or reach thereof extendingbetween the backing plate outer face 55 and the side table inner edge36. This is accomplished before the clamp til is tightened so that afterthe belt d6 is in position as illustrated in Figures 1 and 2, the baseplate 55' may be displaced from right to left away from the largespindle 4 i. and the clamp ts is then, tightened for securing the baseplate ii to the drill chuck table 38 with the belt 46 tensioned. Byslightly loosening the clamp 49 and swinging the base plate Hcounterclockwise relatively to the clamp, as seen in Figure 2,additional tensioning of the belt 46 can be accomplished. The belt 43can also be tensioned by advancing the'sorew 23 downwardly through the.support end 24 rocking the support l counterclockwise on the pivot hasseen in Figure 1, to displace the spindle 22 away from the spindle M.However, ordinarily this is not done but rather the screw 28 is adjustedso that the axis of the spindle 22 will be perpendicular to the baseplate H and parallel to the axis of the spindle 4!. The ends of the belt48 are joined along a diagonal line 41, for a purpose which willhereinafer be described. It will also be apparent that belts 45 ofdifferent lengths may be employedsince the distance between the spindles22 and 4! may be varied substantially as the spindle 51 -is supportedindependentlyof the base plate H. The peripheries of both spindles orpulleys may be provided with a suitable non-slip coating, as indicatedat 48 in Figure 5 in reference to the spindle 4|. Likewise, thediameters of the spindles can be increased by securing a sleevetherearound, such as illustrated in Figure 'l by the sleeve 49 appliedto the spindle 22.

From the foregoing it will be readily apparent that the belt 45 will bedriven when the drill chuck is revolved at diiferent speeds dependingupon the speed of rotation of said drill chuck and as variablycontrolled by the conventional speed change pulleys of the drill press.The end table 11 may be utilized to suport a workpiece for detailedsanding and finishing a rounded portion of small radii, by utilizing theportion of the belt 8 passing around the small spindle 22. By looseningthe fastening 19 the table I! may be tilted at different angles forsupporting a workpiece, not shown, for angle sanding and dressing.

Likewise, the side table 28 can be employed as a rest for a workpiecefor edge sanding utilizing the portion of the reach or flight of thebelt 46 which is passing across the outer face 35 of the backing plateas, said backing plate preventing said belt reach from yielding inwardlyand away from the workpiece. Likewise, the table 28 may be angularlyadjusted for supporting a workpiece for angle sanding and dressing tovarious shapes. Also, detailed sanding and dressing such as roundedcorners of edges and faces of a workpiece may be accomplished where theworkpiece is supported on the table 28 and said table is employe-cl inconjunction with the groove 31 which permits a portion of the beltflight or reach to ield inwardly, for rounding oil corners and edges ofthe workpiece. The end of the table 28 located adjacent the larger beltpulley 4| may be employed in conjunction therewith for larger radiisanding of rounded surfaces.

Furthermore, both tables 11 and 28 may be raised and lowered forutilizing the entire width of the sanding belt 46. The diagonal joint 4!of the sanding belt 46 lessens vibration and tearing oi the belt whichwould otherwise occur due to the sudden jar of a straight joint movinginto engagement with the small spindle 22 and which spindle wouldadditionally tend to rupture a straight joint due to its short radius.

It will thus be apparent that substantially all types of radius and edgesanding of various materials may be effectively accomplished with thesanding attachment 10.

It will also be apparent that the sanding attachment could be utilizedwith a separate electric motor or an electric hand drill suitablysupported rigidly above a workbench or the like to which the base plateH was clamped.

Various other modifications and changes are contemplated and mayobviously be resorted to, without departing from the spirit or scope ofthe invention as hereinafter defined by the appended claims.

We claim as our invention:

1. A belt sander attachment for a power tool having a rotary drivenchuck disposed above a supporting table, comprising a base plate havingone end adapted to rest on a table of a power tool, clamping meansdetaohably securing said base plate end to the table, a spindle of smalldiameter, means supporting and journalling said spinle in substantiallyan upright position above an opposite end of said base plate, a drivepulley of larger diameter than said spindle adapted to be detachablysecured to a rotary chuck of the power tool and supported thereby abovethe table and with the axis or the pulley disposed substantiallyparallel to the axis of said spindle, an endless sanding belt trainedaround said pulley and spindle and driven by rotation of the pulley, anda work supporting table adjustably supported on the base plate andoutwardly of and adjacent a portion of the sanding belt.

2. A sander attachment as in claim 1, said work supporting table havinga depending slotted bar, a standard fixed to and rising from the baseplate, and a fastening extending through the bar slot and through saidstandard for adjustably securing the bar to the standard to support thetable at difierent elevations relatively to the sanding belt and indifferent planes relatively to the plane of an adjacent portion of thesanding belt.

3. A belt sander attachment as in claim 2, a backing plate, meansdetachably and adjustably supporting said backing plate above andsubstantially perpendicular to the base plate and between the beltreaches and with an outer face of the backing plate in engagement withone of the belt reaches, said belt reach extending between said backingplate and an adjacent edge of the workpiece supporting table.

4. A belt sander attachment as in claim 3, said outer face of thebacking plate having a groove extending from end-to-end thereof overwhich a longitudinal portion of said belt reach extends and into whichsaid portion of the belt reach is displaceable.

5. A belt sander attachment as in claim 1, said supporting andjournalling means comprising an elongated support, means pivotallymounting said support above the last mentioned end of the base plateintermediate of the ends of said support for vertical rocking movement,said spindle being mounted on said support outwardly of the pivotthereof, and an adjusting screw extending threadedly through an innerend of the support and bearing on the base plate for adjustably limitingswinging movement of the spindle in a direction toward said pulley.

6. A belt sander attachment as in claim 5, said workpiece supportingtable having a slotted bar fixed to and depending therefrom, andfastening means detachably and adjustably securing said bar to an outerend of the rocking support for adjustably supporting the table forrocking movement with said spindle and for vertical and angularadjustment relatively to the spindle.

7. A belt sander attachment as in claim 6, said workpiece supportingtable having an inner edge provided with a notch for accommodating saidspindle and the belt portion passing therearound.

8. A belt sander attachment as in claim 1, said sanding belt having adiagonal joint.

No references cited.

